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مرکز اطلاعات علمی SID1
اسکوپوس
مرکز اطلاعات علمی SID
ریسرچگیت
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Author(s): 

ZENKOUR A.M. | MATURI D.A.

Journal: 

SCIENTIA IRANICA

Issue Info: 
  • Year: 

    2015
  • Volume: 

    22
  • Issue: 

    2 (TRANSACTIONS A: CIVIL ENGINEERING)
  • Pages: 

    287-298
Measures: 
  • Citations: 

    0
  • Views: 

    21211
  • Downloads: 

    24796
Abstract: 

The thermoelastic bending response is presented for a simply-supported composite LAMINATED PLATE subjected to a thermal field. The sinusoidal PLATE theory as well as classical and other shear deformation theories is used. The LAMINATED PLATE may be composed of one material or a combination of two materials. The layers may be symmetric cross-ply or anti- or non-symmetric angle-ply lay-up. The numerical illustrations concerned with the thermal bending response of the presented rectangular PLATE are studied. The effects due to many parameters, such as shear deformation, aspect ratio, side-to-thickness ratio, thermal loading and elastic foundations, are all investigated.

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Issue Info: 
  • Year: 

    2015
  • Volume: 

    15
  • Issue: 

    2
  • Pages: 

    72-80
Measures: 
  • Citations: 

    0
  • Views: 

    1085
  • Downloads: 

    632
Abstract: 

In this paper, a LAMINATED composite PLATE that was subjected to bending fatigue load was modeled based on the strength degradation theory of the composites. Also, effects of the fiber directions in the layers and layer stacking on the fatigue life of the PLATE were studied. First, the governing equation of the laminate PLATE in bending was obtained by the Navier theory. Then, by solving the governing equation, the deflection and stresses in the plies of each layer were obtained. Finally, using the Brotman-Sahu strength degradation theory, reduction of strength and stiffness in each layer of the PLATE in each loading step was determined. The data obtained in each step were used to specify the data and material properties of the next solution step. This process was repeated until a fatigue failure in the fiber or matrix began in one or more layers. Using the sudden death theory and iteration of the solution process, the final fatigue life of symmetric laminates with various stacking and fiber direction was investigated. In the numerical results, the carbon/epoxy composite laminate with different layer stacking was studied.

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Issue Info: 
  • Year: 

    2019
  • Volume: 

    50
  • Issue: 

    2
  • Pages: 

    375-380
Measures: 
  • Citations: 

    0
  • Views: 

    17812
  • Downloads: 

    5865
Abstract: 

Fiber-reinforced LAMINATED composites are frequently preferred in many engineering projects. With the development in production technology, the using of the fiber reinforced LAMINATED composites has been increasing in engineering applications. In the production stage of the fiber-reinforced LAMINATED composites, porosities could be occurred due to production or technical errors. After a level of the porosity, the mechanical behaviors of composite materials change significantly. This paper presents buckling analysis of fiber-reinforced LAMINATED composite PLATE with porosity effects within the first shear deformation PLATE theory. In the porosity effect, three different porosity models are used in the LAMINATED composite PLATE. The material properties of the laminas are considered as orthotropic property. In the solution of the problem, the Navier procedure is used for the simply supported PLATE. Influences of the porosity coefficients, the porosity models, the fiber orientation angles and the sequence of laminas on the critical buckling loads are presented and discussed.

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گارگاه ها آموزشی
Issue Info: 
  • Year: 

    2016
  • Volume: 

    32-3
  • Issue: 

    1
  • Pages: 

    3-19
Measures: 
  • Citations: 

    0
  • Views: 

    790
  • Downloads: 

    298
Abstract: 

Based on the desirable properties of smart materials, many studies on the application of these materials in the field of vibration control, damage detection, shape control and buckling control have been undertaken. For the design and analysis of smart beams, PLATEs or shells, several considerations, such as the type and number of sensors and actuators and their locations, the method of modelling, and different analyses and the types of control system, are considered.In this paper, vibration control of a LAMINATED composite PLATE, with piezoelectric actuators and sensors, is investigated.Governing equations of the LAMINATED composite PLATE were derived using piezoelectric constitutive equations and Hamilton' s principle. For modelling of the LAMINATED PLATE, one of the numerical mesh-less methods; Element Free Galerkin (EFG), is used. In such methods, for discretization of a continuous field, a scattered set of particles instead of elements are distributed in the field, and the method of moving least squares (MLS) is used to construct the shape functions. In order to model the displacement and strain field of the LAMINATED PLATE, the first-order shear deformation theory (FSDT) is used to consider its shear deformation effects.To verify the results, the natural frequency of isotropic and orthotropic PLATEs with different boundary conditions was calculated and compared with other studies.The accuracy of the piezoelectric modelling is verified by calculating the displacement in different points of a bimorph piezoelectric beam in response to applying the electrical potential. After verification of the proposed method, the Newmark method is used to solve the dynamic equations of the LAMINATED composite PLATE. For active vibration control of the LAMINATED PLATE, a feedback control algorithm is used. The model is applied for the solution of two illustrative cases and the results are presented and discussed.

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Issue Info: 
  • Year: 

    2018
  • Volume: 

    34-3
  • Issue: 

    1
  • Pages: 

    105-115
Measures: 
  • Citations: 

    0
  • Views: 

    154
  • Downloads: 

    147
Abstract: 

Trapezoidal fiber reinforced composite PLATEs are important structural elements in modern engineering industries. In this paper and for the first time, the free vibration analysis of LAMINATED composite trapezoidal PLATE resting on the Pasternak type foundation has been presented. First, the kinetic and strain potential energies of the LAMINATED composite PLATE based on the classical PLATE theory are formed. Then by using the change of variables, the trapezoidal PLATE is mapped into the rectangular one. Next, we have assumed the deflection of the PLATE as a series having orthogonal terms and unknown coefficients. It is worth mentioning that the admissible polynomials for all possible combinations of classical boundary conditions have been presented in the paper. The deflection is approximated by a set of beam characteristic orthogonal polynomials generated using the Gram-Schmidt procedure. A sufficiently large number of truncated series have been worked out to make sure the convergence criteria. These polynomials have to satisfy the essential boundary conditions of the PLATE. Upon substituting the above stated response in the energies terms, they have been rewritten in terms of the unknown coefficients. At the end by applying the Ritz method, a standard eigenvalues problem is obtained out of which the frequencies and corresponding mode shapes can be obtained. The obtained algorithm is very general and it is attractive regarding its versatility in handling any classic boundary conditions. Besides, it allows taking into account a great variety of anisotropic characteristics and geometric planforms. In order to establish the validity, accuracy and applicability of the described approach and self-developed computer program, numerical results have been computed for a number of PLATE problems for which comparison values are available in the literature. Excellent agreements are observed. Additionally, new results are also presented for PLATEs under different conditions to investigate the influences of different parameters on the vibrational characteristics of the PLATE. For some PLATEs, mode shapes of free vibration are also shown.

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Issue Info: 
  • Year: 

    2015
  • Volume: 

    15
  • Issue: 

    9
  • Pages: 

    95-104
Measures: 
  • Citations: 

    0
  • Views: 

    617
  • Downloads: 

    229
Abstract: 

In this study out of plane active vibration control of a LAMINATED composite rectangular PLATE with intermediate line support coupled with piezoelectric patches on both sides, upper and lower surface of the PLATE, is presented based on First order shear deformation PLATE theory (FSDT). Is this study, the piezoelectric patch is used as a sensor. In the relation of piezoelectric, electrical potential in the transverse direction is earned by satisfying electric boundary conditions (open circuit) and Maxwell's electricity equation. The Rayleigh-Ritz approach is used to obtain natural frequencies and vibration mode shapes of the PLATE. Forced vibration response is obtained by using by the modal expansion method. In this paper, the Linear Quadratic Regulator (LQR), Linear Quadratic Gaussian (LQG) and Fuzzy Logic Controller (FLC) are used to control and reduce the amplitude of the transverse deformation of a LAMINATED composite rectangular PLATE which is excited by external force. In the numerical results, the effect of various inputs, e.g. positions of the external force, on the responses of the system are examined and discussed in detail. The proposed analytical method is validated with available data in the literature.

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strs
Author(s): 

KAVIANI F. | MIRDAMADI H.R.

Issue Info: 
  • Year: 

    2013
  • Volume: 

    12
  • Issue: 

    6
  • Pages: 

    147-158
Measures: 
  • Citations: 

    1
  • Views: 

    676
  • Downloads: 

    299
Abstract: 

In this paper, a novel four-variable refined theory of PLATE, called RPT, has been proposed for free vibration of composite LAMINATED PLATEs, using a hyperbolic sine function, for calculating out-of-plane shear strains. It is one of the properties of this theory that the boundary condition of zero shear stress is satisfied over upper layer and under lower layer of PLATE, with no reference to Timoshenko shape factor. In contrast to other higher-order shear deformation theories, in RPT theory, equations of motion are coupled dynamically only in inertial terms, while elastic energy terms are not coupled for the variables used. From this viewpoint, RPT theory is similar to classical PLATE theory (CLPT). Some of the objectives of this paper are the investigation of effect of influential parameters on fundamental frequency, such as modulus ratio, angle of plies, and PLATE length-to-thickness ratio. The results of this proposed version of RPT are compared and validated with those of first-order shear deformation theory (FSDT), higher-order shear deformation theory (HSDT), and the original version of RPT.

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Author(s): 

CANDIOTTI S. | MANTARI J.L.

Issue Info: 
  • Year: 

    2018
  • Volume: 

    4
  • Issue: 

    4
  • Pages: 

    331-351
Measures: 
  • Citations: 

    0
  • Views: 

    31915
  • Downloads: 

    18269
Abstract: 

This paper presents Best Theory Diagrams (BTDs) constructed from various non-polynomial theories forthe static analysis of thick and thin symmetric and asymmetric cross-ply LAMINATED PLATEs. The BTD is a curve thatprovides the minimum number of unknown variables necessary for a fixed error or vice versa. The PLATE theories thatbelong to the BTD have been obtained by means of the Axiomatic/Asymptotic Method (AAM). The different PLATEtheories reported are implemented by using the Carrera Unified Formulation (CUF). Navier-type solutions have beenobtained for the case of simply-supported PLATEs loaded by a bisinuisoidal transverse pressure with different lengthto-thickness ratios. The BTDs built from non-polynomials functions are compared with BTDs using Maclaurinexpansion. The results suggest that the PLATE models obtained from the BTD using non-polynomial terms can improvethe accuracy obtained from Maclaurin expansions for a given number of unknown variables of the displacement field.

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Author(s): 

TORABIZADEH M.A. | FEREIDOON A.

Issue Info: 
  • Year: 

    2017
  • Volume: 

    4
  • Issue: 

    1
  • Pages: 

    75-87
Measures: 
  • Citations: 

    0
  • Views: 

    28675
  • Downloads: 

    11576
Abstract: 

n analytical and numerical solution for the free vibration of LAMINATED polymeric composite PLATEs with different layups is studied in this paper. The governing equations of the LAMINATED composite PLATEs are derived from the classical LAMINATED PLATE theory (CLPT) and the first-order shear deformation PLATE theory (FSDT). General layups are evaluated by the assumption of cross-ply and angle-ply LAMINATED PLATEs. The solver is coded in MATLAB. As a verification method, a finite element code using ANSYS is also developed. The effects of lamination angle, PLATE aspect ratio and modulus ratio on the fundamental natural frequencies of a LAMINATED composite are also investigated and good agreement is found between the results evaluated and those available in the open literature. The results show that the fundamental frequency increases with the modular ratio and the bendingstretching coupling lowers the vibration frequencies for both cross-ply and angle-ply laminates with the CLPT. Also it is found that the effect of bending-stretching coupling, transverse shear deformation and rotary inertia is to lower the fundamental frequencies.

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Issue Info: 
  • Year: 

    2021
  • Volume: 

    9
  • Issue: 

    3
  • Pages: 

    3-14
Measures: 
  • Citations: 

    0
  • Views: 

    0
  • Downloads: 

    0
Abstract: 

The present study develops a semi-instantaneous baseline damage identification approach to identify the delamination damage. An active sensing network with (Ba0. 95Ca0. 05)(Ti0. 91Sn0. 09)O3 (BCTS) lead-free piezoelectric transducers that were mounted on the two undamaged and damaged (with the delamination) PLATEs. The wavelet transform was used for extracting the energy ratio change which is an effective and robust characteristic from the collected time-domain signals. The “, identicality coefficient”,(IC) was obtained for each sensing path under pristine structural conditions and used to eliminate any inequalities in the signals of each path. The output wave signals of samples were investigated by experiment and the finite element method. The values of the index produced by damages were significant against the threshold value set. The errors were less than 4%, which may be related to the linear relationship considered for the DI and delamination damage. A comparative of sensing paths showed a significant difference between both healthy and damaged samples. The deLAMINATED damage was detected because the delamination phenomenon increased the amplitude of the wave and the wave energy. The comparison of the “, damage index”,(DI) values of six sensing paths showed that the path with delamination damage had the highest DI value i. e., 0. 92 and then the sensing paths closest to the damage showed the highest DI values (DI=0. 67). The path with a distance farther from the damage shows DI=0. 09. The other DI values of other sensing paths were close to zero (DI=0) due to no damage.

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